A bomb has exploded in the printing plant of a privately-owned newspaper in Zimbabwe which has been critical of the government.

The attack on the Daily News follows a recent warning by the Information Minister, Jonathan Moyo, that it was only a matter of time before Zimbabweans put a stop to what he called the newspaper's "madness".

Windows were blown out and part of the roof torn off by the explosion in the early hours of the morning. No one was injured.

They went straight to the unit that was operating and placed their explosives

Deputy editor Davison Maruziva

The paper's deputy editor, Davison Maruziva, said the printing press had been badly damaged and staff were trying to find a way to put out Monday's edition.

The BBC's Grant Ferrett in Harare said the Daily News, which regularly outsells its main state-run rival, has become the focus of government anger in recent weeks because of its repeated criticism of the authorities.

Wall breached

The attackers demolished part of a concrete security wall and tore off metal doors to get into the plant.

''They were experts and they went straight to the unit that was operating and placed their explosives,'' Mr Maruziva said.

He said security guards at the plant had been threatened by the bombers and had run off.

Police arrested and questioned three senior Daily News journalists on Friday. The same day, the militant leader of Zimbabwe's independence war veterans, Chenjerai Hunzvi, said they had resolved to ''ban'' the newspaper.

Protests

On Tuesday, supporters of the ruling ZANU-PF party marched on the Daily News offices in protest at a report that Zimbabweans had celebrated the death of DR Congo's President Laurent Kabila earlier this month.

Zimbabwe's President Mugabe has backed the Kabila regime with thousands of troops.

During the demonstration, protesters assaulted the Daily News reporter who was covering the event.

Last June, a bomb destroyed a gallery beside the Daily News' editorial offices after several government officials criticised its coverage of political violence in the run-up to parliamentary elections.